Photographic emulsions



PHOTOGRAPHIC EMULSIONS Comer Drake Shacklett, Roselle, N. J., assignorto E. I. do Pout de Nemours and Company, Wilmington,Del., a corporationof Delaware No Drawing. Application February 7, 1955 Serial No. 486,696.1

19 Claims. (Cl. 96-114) This invention relates to photography and moreparticularly to photographic emulsions in which the binding agentcomprises an addition polymer containing extralinear amide groups andextralinear betaine and/ or glycol groups. Still more particularly, itrelates to emulsions of. light-sensitive silver halide in ,awater-permeable colrelates to silver halide photographic emulsions inwhich synthetic polyamides containing betaine and/or glycol groups (asdescribed in U. S. application Ser. Nos. 415,161, 415,162 and 415,163,filedMarch 9, 1954), are used instead of all or part of the gelatinwhich is ordinarily the carrier, binder and protective colloid for thelight-sensitive agent. I

Heretofore, gelatin has been employed as the carrier, for thelight-sensitive silver halide in commercial highspeed negative typephotographic emulsions. However, this substance has numerousdisadvantages and it has long been sought to obtain a substitutetherefor which possesses the advantages of gelatin with a minimum of itsdisadvantages. Many materials have been proposed for this purposeincluding natural and synthetic colloids and polymers having hydrophilicproperties. The previously proposed materials have the seriousdisadvantage that photographic emulsions with speeds equivalent to thoseof high-speed negative type gelatino-silver halide emulsions cannot bemade in them. I

An object of this invention is to provide silver halide emulsions insynthetic colloids which are free fromthe disadvantages of gelatin andrelated natural protein colloid emulsions. Another object is to providesuch emulsions which have speeds at least as high as those obtainablewith gelatin. Yet another object is to' provide emulsions of silverhalide in synthetic addition polymers that are uniform, stable,resistant to bacteria and from thin layers which are flexible over awide range of temperatures. A further object is to prepare suchemulsions which can be admixed with an additional amount of the same oranother polymeric colloid and/or gelatin. A still further object is toprepare such emulsions in which polymeric and other non-diffusing colorformers are readily dispersible and the developed photographic layersare free from haze and other disadvantages. Still other objects will beapparent from the above description of the invention.

The photographic emulsions of this invention, in their broader aspects,consist essentially of a dispersion of light-sensitive silver halide ina water-permeable colloid binding agent wherein at least 2% by weightof' such agent is an addition copolymer having hydrophilic propertiescomposed of a substantial number of recurring intralinear units (a) ofat least one of the types taken from the group consisting of thosehaving Formula I and those having Formula I and (b) at least one type ofa unit having Formula II (each of saidformulae being given below). Theremaining proportion of the binding agent can be a dilferent copolymerof the same type and/or a dififerent compatible water-permeable colloid,preferably gelatin, polyvinyl alcohol, or a polyvinyl acetal havinghydrophilic colloid properties, including p-hydroxbenzaldehyde polyvinylacetal, sodium o-sulfobenzaldehyde polyvinyl acetal and polyvinylacetals containing color former nuclei linked to the polyvinyl alcoholby an acetal linkage.

Copolymers containing one each of the types of units having Formula Iand II and their preparation are described in Shacklett U. S.application Ser. No. 415,163,

filed March 9, 1954. These copolymers arecomposed of recurringintralinear units of the formulae:

. R2\ /Rl l I R-J:CoNHR1N+R'co0- H: I l wherein R is a member taken fromthe group consisting of hydrogen, alkyl radicals of 1 to 3 carbon atoms,phenyl andcyclohexyl, R is a saturated divalent, aliphatic hydrocarbonradical of 2 to 6 carbon atoms, R is an alkyl radical of l to 3 carbonatoms, R, is an alkyl radical of l to 3 carbon atoms, and R' is asaturated divalent, aliphatic hydrocarbon radical of lto 4 carbon atoms,and

/R n a-bn con wherein R, R" and-R are members taken from the groupconsisting of hydrogen, alkyl of 1 to 3 carbon atoms, phenyl andcyclohexyl. These copolymers may contain one, two or more diiferentunits of the type of Formula I and one, two or more different units ofthe type of Formula II. In the'se'copolymers, units of type I arepresent in an amount of 5 to 80 mol percent and the copolymers have amolecular weight of at least 5,000.

Copolymers containing one each of the types of units having Formula Iand II and their preparation are described in Shacklett U. S.application Ser. No. 415,162, filed March 9, 1954, and the applicationsreferredto units of the formula:

wherein R is a member taken from the group consisting of hydrogen, alkylof 1 to 3 carbon atoms, phenyl and cyclohexyl, R is a member taken fromthe group consisting of hydrogen and alkyl of 1 to 3 carbon atoms, R" isa member taken from the group consisting of hydrogen and alkyl of l to 3carbon atoms, In is a cardinal number from 0 to 4, and n is a cardinalnumber 0 to 1 and the sum of m and n equals at least 1. Units of type Iconstitute 10 to mol percent of the copolymers, which have molecularweights of at least 5,000.

Copolymers containing three intralinear units, namely thoseof FormulaeI, I and H and their preparation are described in Shacklett U. S.application Ser. No. 415,161,

filed March 9, 1954, and in the applications referred to March 9, 1954,with the following changes: 600 parts of water and 157.2 parts ofisopropyl alcohol were placed in the polymerization vessel instead of800 parts of water, 48.4 parts of N,3-methacrylamidopropyl-N,N-dimethyl-B-aminopropionate betaine was used instead of 45.6 parts ofN,2-methacrylamidoethyl-p-aminopropionate betaine, the hydrolysis of thedioxolane was carried out in a mixture of 150 parts of water and 39.3parts of isopropyl alcohol, the yield of the resulting copolymer was 101parts and the relative viscosity of a 1% aqueous solution thereof at 30C. and pH 7 was 2.61, was used instead of the copolymer described inExample 1.

A similar emulsion containing gelatin as the sole binding agent wasprepared and coated as described in Example l. Samples of the two filmswere exposed and processed as described in Example 1. The relative speedof the film containing the copolymer was 229 compared with the gelatincontrol film whose relative speed was 100 and was equal to that which ischaracteristic of currently available high-speed negative typephotographic films.

Example 6 A photographic emulsion was prepared by precipitating by meansof aqueous silver nitrate, ammonium bromide 2 and potassium iodidesolutions, 141.6 parts of silver iodobromide (in which the ratio ofsilver iodide to silver bromide was 1123.7) in the presence of 11 partsin aqueous solution of the copolymer of methacrylamide andN,2-methylacrylamidoethyl-N,N-dimethyl-B-aminopropionate betaineprepared as described in Example 3 above. After precipitation, Ostwaldripening was carried out in the presence of excess bromide ion andammonia. Thereafter, an additional portion of 40 parts of the samecopolymer was added as a 10% aqueous solution and the polymer afterthorough mixing, was precipitated by the addition of a large excess ofacetone. The precipitated copolymer containing the silver halide waswashed with aqueous methanol, then redissolved in a 10% aqueous solutionof 169 additional parts of the same copolymer, and digested with theconventional additions, of water, sensitizing, and dispersing agents,etc. being made after which it was coated on a paper support and dried.

A similar emulsion was made in gelatin as the sole binding agent asdescribed in Example 1 above and this emulsion was also coated on paperand dried. When samples of these two papers were exposed in a negativetype 1B sensitometer, developed, fixed, washed and dried under identicalconditions the relative photographic speed of the product made withgelatin was 200 compared with'that made with the copolymer which was100, and was characteristic of currently available high-speed negativetype photographic emulsions.

Example 7 Example 8 The procedure of Example 6 was repeated with a V:mixed polyvinyl acetal of orthosulfobenzaldehyde and'N-m(3-methylsalicylamido)benzaldehyde similar to that described in U.S. Patent No. 2, 489,655, but containing 20 to 30% of each of the twoaldehyde residues, used to -.replace those portions of the polymerdescribed in Ex- .ample 6 that were employed after the ripening of the:silver halide was completed. Because this polyvinyl acetal is gellableby use of borate ion as a cross-linking agent, this emulsion was coatedon a support having a layer containing a borate ion as described in U.S. Patent 2,534,326.

A similar emulsion was made in which the precipitating and ripening ofthe silver halide was done in the presence of 11 parts of gelatin ratherthan in the copolymer described in Example 6. The remainder of theprocedure was as described in that example. When samples of these twofilms were exposed in a sensitometer, and processed according to theprocedure described by Jennings et al., Journal of the Society of MotionPicture and Television Engineers, volume 55, pages 469 through 471,November 1950, they had the same photographic speed, and the saturationand hue of their photographic images were indistinguishable.

Example 9 The procedure of Example 6 was repeated with the 5 scribed inExample 6. Because the polymer of Example Example 0 The procedure ofExample 7 was 'repeated with the exception that a copolymer ofmethacrylamide and N,2,3- dihydroxypropyl-methacrylamide, prepared asdescribed in Table 1, Experiment 2 of Example 1 of U. S. applicationSer. No. 415,162, filed March 9, 1954, except that the solvent for thepolymerization'consisted of a mixture of 375 parts of water and 98.3parts of isopropyl alcohol, and the relative viscosity of 1% aqueoussolutions of the resulting polymer at 30 C. and pH 7 was1-.21, wasusedinstead of the copoymer, described in Example 6.-

The photographic speed of the product obtained in this experiment wasessentially the same as thatobtained in Example 8.

Example 11 The procedure of Example 10 was repeated with the exceptionthat the methacrylamide copolymer described in Example 5 was usedinstead of that mentioned in Example 10. The photographic speed of theproduct obtained here was similar to that reported in Example -7.

Example 12 A photographic emulsion was prepared by precipitating bymeans of aqueous silver nitrate, ammonium bromide, potassium bromide andpotassium iodide solutions from aqueous solution, 140.8 parts of silveriodobromide (in which the ratio of'silver iodide to silver bromide was1:50.1) in the presence of 24 parts in aqueous solution of a copolymerof methacrylamide and N,2-methacrylamidoethyl-N,N-dimethyl-l8-aminopropionate betaine, prepared as described inExample 1 of U. S. application Ser.'No; 415,163, filed March 9, 1954.After precipitation, Ostwald ripening was carried out in the presence ofexcess bromide ion and ammonia. Thereafter, 182.5 parts of gelatin wasadded and dissolved in the mixture: The emulsion was then cooled to forma firm gel, broken up and washed with water to remove soluble compounds.The washed gel was melted, and digested with the conventional-add? 7tion's-of water, sensitizing and dispersing agents, hardeners, etc.,being made after which it was coated on a celluloseacetate support anddried.

A similar emulsion was made .in the identical fashion with the exceptionthat 24 parts of gelatin was substituted for the 24 partscofthecopolymer used during the precipitation. and ripening stage and thisemulsion was also coated on a celluloseaceta'te support and dried. Whensamples of the two films were exposed in a positive type 1Bsensitometer, developed, fixed, washed anddried under identicalconditions, the'relative photographic speed of the film containing thecopolymer was 213 compared with the gelatin control whose relative speedwas 207 and was equal to that which is characteristic of currentlyavailable highest speed cine positive film s.

Still other soluble polyami'des'of the type disclosed in U. S.application Ser. Nos. 415,161, 415,162 and 415,163 can be employed asprotective colloid, bulking and binding agent for the silver halide inplace of or in addition to those described in the foregoing examples.Among such compounds may be mentioned Poly(methacrylamide coN,2,3-dihydroxypropylacrylamide coN,2-acrylamidoethyl-N,N-dimethyl-fl-aminopropionate-betaine)Poly(methacrylamide co N,2,3-dihydroxypropylacrylamidev coN,3-methacrylamidopropyl-N,N-dimethyl arninoacetate betaine)Poly(methacrylamide co N,2,3-dihydroxypropylmethacrylamide 'coN,2-acrylamidoethyl-N,N-dimethylaminoacetatebetaine) Poly(methacrylamideco N,2-methacrylamidoethyl-N,N-

dimethylaminoacetate betaine) Poly(methacry-lamide coN,3-methacrylamidopropyl-N,N- dimethylaminoacetate betaine),

Poly(methacrylamide co N,2-methacrylamidoethyl-N,N-

diethylaminoacetate betaine) Poly(methacrylamide coN,3-methacrylamidopropyl-N,N-

diethylaminoacetate betaine) Poly(rnethacrylarnide coN,3-acrylamidopropyl-N,N-dimethyl-fl-aminopropionate betaine)Poly(methacrylam'ide coN,2-acrylamidoethyl-N,N-dimethyl-,B-aminopropionate betaine)Poly(rnethacrylamide co N,2-acrylamidoethyl-N,N-dimethylaminoacetatebetaine) Poly(methacrylamide coN,3-acrylamidopropyl-N,N-diethylaminoacetatebetaine), and

Poly(m'ethacr'ylamide co N,2,3'-dihydroxypropylacrylamide) 1 a In all ofthe above examples in which a hydroxylated polymer was used,greatimprovement in the toughness, permanence, resistance to-abrasion wasobtained by crosslinking the copolymer by treatment with solutions ofthe titanium compounds described in U. S. application Ser. No. 433,286,filed May 28, 1954.

The invention is not limited to the specific lightsensitive materialsdescribed inthe above detailed examples. On the contrary, various othersimple and mixed silver halidesmay be used as the light-sensitivematerials,

in, like manner. Mixtures of silver bromide, chloride and/or iodidecanbe made by adding mixtures of soluble salts of these halides in likemanner. Other useful soluble halides include potassium bromide,potassium iodide, sodium, potassium and ammonium iodides, chlorides andbromides, etc. Other useful soluble silver salts include silversulfamate, silver sulfate, silver citrate and silver acetate.

During" thedigestion stage or prior thereto, various typesof-sensitizingagents, e; g., sulfur sensitizers, such as flllylthioureas,thiocyanates, thiosulfates, allylthiocyanates, andiother organic orinorganic sulfur sensitizers can be added." In addition, various metalsensitizers may also be addedu suchas those normally used in gelatinemulsions and known to those skilled, in the art .of photographicemulsion manufacture. .In addition, various types of optical sensitizingdyes which modify the spectral characteristics of theresulting emulsionscan be added. Suitable sensitizing dyes are described in U. S. Patents2,010,388, 2,079,376, 2,202,990, 2,202,991, 2,202,992,. 2,278,461,2,265,908, etc. Similarly desensitizingdyes canbe used when it isdesired to make fogged emulsions for direct positives.

Various types of color forming aldehydes maybe used in forming thepolyvinyl acetals used in certain specific embodiments of this inventionSuitable such aldehydes and polyvinyl acetals are described in U. S.Patents 2,476,986, 2,476,987, 2,476,988, 2,472,910, 2,518,704,2,538,259, 2,513,190, 2,513,189. Noncolor forming aldehydes may also beused in preparing these poly.- vinyl mixed acetalssuch as, for example,ortho-sulfobenzaldehyde, benzaldehyde, pehydroxbenzaldehyde, etc.

Thesynthetic polyamides described above are completely free from sulfur,metal, and other sensitizing materials, yet allow the preparation ofsilver halide grains of such type that these sensitizing materials canbe added at or prior to the digestion stage in the emulsion manufactureand stillrexert their full sensitizing effects.

An important advantage of the invention is that it provides photographicemulsions having the high-speed characteristics desirable in negativefilms. is that silver halide emulsions of uniform characteristics can bemade readily. A furtltier advantage is that the use of the syntheticpolyamides described above admit of the precipitation and growth ofsilver halide grains which are potentially as sensitive to light as thehigh-speed negative emulsions made with gelatin. Still other advantageswill be apparent from the above description of the invention.

The embodiments of the-invention in which an ex elusive property orprivilege is claimed are defined as follows:

1. An emulsion of light-sensitive silver halide in a. water-permeablecolloid binding agent wherein at least 2% by'weight is an additioncopolymer having hydrophilic properties composed solely of a substantialnumber of recurring intralinear units of (a) at least one type of unittaken from the group consisting of those of formulae:

R: R: R-rl*'G 0 NH Ri- -N+ -R'0 0 oa.. I wherein R is amember taken fromthe group consisting of hydrogen, alkyl radicals" of 1 1 to 3 carbonatoms, phenyl and 'cyclohexyl, R is a saturated divalent, aliphatichydrocarbon radical of 2 to 6 carbon atoms, R, is an of hydrogen,alkyl'of 1 to 3 carbon atoms, phenyl and cyclohexyl, R is a member takenfrom the group consisting of hydrogen and alkyl of 1 to 3' carbon atoms,

R is a member taken ,from the group consisting of hydrogen and alkyl of1 to 3 carbon atoms, m is a cardinal number from Oto 4, n is acardinalnumber from 0 to 1 and the sum of m and n equals at least 1 and(b) at least one type ofunit of the formula:

Another advantage wherein R, R" and R are members taken from the groupconsisting of hydrogen, alkyl of 1 to 3 carbon atoms, phenyl andcyclohexyl. said unit (a) being present in an amount of at least molpercent.

2. An emulsion as set forth in claim 1 wherein substantially 100% of thebinding agent is selected from the group of copolymers recited in claim1 p 3. An emulsion as set forth in claim 1 wherein the rest of thebinding agent is gelatin.

4. An emulsion as set forth in claim 1 wherein the rest of the bindingagent is a polyvinyl acetal.

5. An emulsion of lighbsensitive silver halide in a water-permeablecolloid binding agent wherein at least 2% by weight is an'additio'ncopolymer having hydrophilic properties composed solely of a substantialnumber of intralinear units of the formulae:

wherein R is a member taken from the group consisting of hydrogen, alkylradicals of 1 to 3 carbon atoms, phenyl and cyclohexyl, R is a saturateddivalent, aliphatic hydrocarbon radical'of 2 to 6 carbon atoms, R2 is analkyl radical of 1 to 3 carbon atoms, R is an alkyl radical of 1 to 3carbon atoms, and R is a saturated divalent,

aliphatic hydrocarbon radical of 1 to 4 carbon atoms,

and

wherein R, R" and R are members taken from the group consisting ofhydrogen, alkyl of l to 3 carbon atoms, phenyl and cyclohexyl, whereinthe first type of unit is present in the amount of 5 to 80 mol percent.

6. An emulsion as set forth in claim 5 wherein substantially 100% of thebinding agent is selected from the group of copolymers recited in claim5.

7. An emulsion as set forth in claim 5 wherein the rest of the bindingagent is gelatin.

8. An emulsion as set forth in claim 5 wherein the rest of the bindingagent is a polyvinyl acetal.

9. An emulsion of light-sensitive silver halide in a water-permeablecolloid binding agent wherein at least 2% by weight is an additioncopolymer having hydrophilic properties composed solely of a substantialnumber of intralinear units of the formulae:

wherein R is a member taken from the group consisting of hydrogen, alkylof 1 to 3 carbon atoms, phenyl and cyclohexyl, R' is a member taken fromthe group consisting of hydrogen and alkyl of 1 to 3 carbon atoms, R isa member taken from the group consisting-of hydrogen and alkyl of 1 to 3carbon atoms, m is a cardinal number from 0 to 4, n is a cardinal numberfrom 0 to 1 and the sum of m and n equals at least 1, and

I H. RI" wherein R, R" and R" are members taken from the groupconsisting of hydrogen, alkyl of 1 to 3 carbon atoms, phenyl andcyclohexyl, wherein the first type of unit is present in the amount ofto 70 mol percent.

10. An emulsion as set forth in claim 9' wherein substantially 100% ofthe binding agent is selected from the group of copolymers recited inclaim 9.

the group of copolymers recited in claim 13. v

15. An emulsion as set forth in claim 13 wherein'the 11.'An emulsion asset forth in claim 9 rest-of the binding agent is gelatin. 1

12. An emulsion as set forth in claim 9 wherein the rest of the'bindingagent is a polyvinyl acetal.

13.An emulsion of light-sensitive silver halide in a water-permeablecolloid binding agent wherein at least 2% by weight is an additioncopolymer having hydrophilic properties'composed solely of a substantialintralinear units of the-formulae:

wherein R is a member taken from the group consisting of hydrogen, alkylradicals of 1 to 3 carbon atoms, phenyl and cyclohexyl, R, is asaturated divalent, aliphatichydrocarbon radical of 2 to 6 carbon atoms,R is an alkyl radical of 1 to 3 carbon atoms, R is an alkyl radical of 1to 3 carbon atoms, and R is a saturated divalent, aliphatic hydrocarbonradical of l to 4 carbon atoms, and

wherein the wherein R is a member taken from the group consisting ofhydrogen, alkyl of l to 3 carbon atoms, phenyl and cyclohexyl, R' is amember taken from the group consisting of hydrogen and alkyl of l to 3carbon atoms, R is a member taken from the group consisting of hydrogenand alkyl of 1 to 3 carbon atoms, m is a cardinal number from 0 to 4, nis a cardinal number from 0 to 1 and'the sum of m and n equals at least1, and

wherein R, R" and R' are members taken from the group consisting ofhydrogen, alkyl of l to 3 carbon atoms, phenyl and cyclohexyl, whereinthe types of units are in the proportions of 5 to 60, 5 to 60 and 30 tomol percent respectively.

14. An emulsion as set forth in claim 13 wherein substantially of thebinding agent is selected from rest of the binding agent is gelatin.

16. An emulsion as set forth in claim 13 wherein the rest of the bindingagent is a polyvinyl acetal.

17. The process which comprises precipitating lightsensitive silverhalide in an aqueous solution containing an addition copolymer havinghydrophilic properties composed solely of a substantial number ofrecurring intralinear units of (a) at least one type of unit taken fromthe group consisting of those of formulae:

1 R-L|3-C ONHR1N+R-C 0 0- (EH: wherein R is a member taken from thegroup consisting of hydrogen, alkyl radicals of 1 to 3 carbon atoms,phenyl and cyclohexyl, R is a saturated divalent, aliphatic hydrocarbonradical of 2 to 6 carbon atoms, R is an alkyl radical of 1 to 3 carbonatoms, R; is an alkyl radical of 1 to 3 carbon atoms, and R is asaturated divalent, aliphatic hydrocarbonradical of l to 4 carbon atoms,and

R! R-dlH-C ONE-(CH1) ,..i oHR" IHI H01:

number of new!!!" whereimk'lis a member taken; from the group consistingof hydrogen, alkyl of 1 to 3 carbongatoms phenylandh cyclohexyLRfis amember taken from the group consisting of hydrogen and alkyl of 1 to 3carbonatoms R" is amember. taken from thegroup consisting of.hydrogerrancl; alkylof 1 to 3 carbon atoms, m is a cardinalnumber-fromOi to 4, n is-a cardinal number from Otto 1 and snm ofqm andn equals at least 11 and (b). at

least one type of unit of theformula:

wherein R, R" and R' are members taken from the gronp consi sting' ofhydrogen, alkyl of 1 to 3 carbon atoms, phenyl and cyclohexyl, saidunit" (a) being present inlan :amount of at least 5- mol percent;ripening thezemulsion, coagulating, the if emulsion, washingthe-'coagulum';

and "admixing additional water-permeable colloid with the washedemulsion.

18. A- process as set forth in claim 17 wherein said colloid is gelatin.

19. A process .as setforth in claim 17 ivherein said colloidlisa;polyviny1 acetal;

References Cited in the file of this patent" UNITED STATESPATENTS

1. AN EMULSION OF LIGHT-SENSITIVE SILVER HALIDE IN A WATER-PERMEABLECOLLOID BINDING AGENT WHEREIN AT LEAST 2% BY WEIGHT IS AN ADDITIONCOPOLYMER HAVING HYDROPHILIC PROPERTIES COMPOSED SOLELY OF A SUBSTANTIALNUMBER OF RECURRING INTRALINEAR UNITS OF (A) AT LEAST ONE TYPE OF UNITTAKEN FROM THE GROUP CONSISTING OF THOSE OF FORMULAE: